Oiling system for outboard motor drive shafts



July 20, 1954 E. c. KIEKHAEFER 2,684,051

OILING SYSTEM FOR OUTBOARD MOTOR DRIVE SHAFTS Filed Dec. l', 1948 EzmerCKekhae er JNVENTo ATTaRNEYs.

Patented July 20, 1954 `UNITED STATES iATNT OFF-ICE OIIING SYSTEM FOR OUTBOARD MOTOR DRIVE SHAFTS Elmer Carl Kiekhaefer, Cedarburg, Wis.

lApplicationDecember 17, 1948, Serial No. 65,807

2 Claims. 1 This invention relates to 4internal combustion engines and particularly to the lubrication of `certain bearing members of two-cycle outboard `marine engines.

A principal object ofthe invention is to provide for the supply of lubricant to certain bearing members during operation of the engine and for positive closing of the supply when the engine is not operating.

Another object is to provide a steady, uniform oiling of the drive shaft and other parts exposed the invention will be more 'fully set forth in the t following description of a preferred embodiment of the invention as illustrated in the accompanying drawing.

In the drawing:

Figure l is a side elevation of the upper part `of an outboard motor with portions thereof broken vaway and sectioned;

Fig. 2 is a diagrammatic view looking upwardly toward the motor showing the relative positions of the oil passages and the engine piston at lower dead center and in an open-position;

Fig. 3 is'a view similar to Fig. 2 showing the piston between dead centers; and

Fig. 4 is a partial View similar to Figi of `the lower crankcase bearing of the engine shown in Figure 1 with a single, valve-controlled drain passage.

The engine shown in the drawing comprises a crankcase l and cylinderblock 2 provided -with two parallel upper and lower cylinders 3 and il. The vertical crankshaft 5 is journaled on upper and lower bearings 6 and 'l in crankcase l and carries the ilywheel 8 at the upper end. The pistons 9 operating within respective cylinders 3 and 4 are connected to crankshaft E by the connecting rods I0. The center crankshaft bearing and valve unit il controls the induction of air and fuel including the engine lubricant from the carburetor i2 into the respective upper and lower crank chambers I3 and I4.

(Cl. 12S-196) The two-cycle, two-cylinder engine is alternately fired by the spark plugs I5 and an electrical ignition system, not shown, operated by crankshaft 5 within flywheel 8. ln Vthe downstroke of each piston the fuel within the Arespective crank chamber is compressed. The ports E8 and il in opposite sides of the cylinders 3 and i are uncovered by pistons 9 at the end of their downward stroke. The exhaust passage I8 inone side of cylinder block 2 receives the exhaust from the cylinder through ports i5. A passage I9 ,in the other side of block 2 communicates with the respective crankcase chamber and provides :for transfer of the compressed fuel from the `charnber to the cylinder through ports il. During `the upward stroke of pistons El the fuel transferred to the respective cylinder is compressed for ignition while a new charge of air and fuel is drawn from carburetor i 2 through valve unit II into the respective crank chamber.

The outboard motor drive shaft housing 2i] supports the engine crankcase I and cylinder block 2 at its upper end and carries the propeller and underwater unit, not shown, at the vlower end. rihe upper end of houusing 2t is open and communicates with passage I 8 opening downwardly of cylinder block 2 to receive the exhaust gases therefrom and discharge the gases Iunder water.

The drive shaft 2l drivingly connected to the propeller, not shown, extends vertically downwardly within housing 2t from the lower opening 22 of crankcase i. The upper end of drive shaft 2l is splined as at 23 to fit within and engage the splined section 2li of the lower end of crankshaft E.

The annular channel E5 around crankshaft 5 immediately below bearing l is provided to collect the heavier fuel deposited in the lower crank chamber id. The portion of crankshaft 5 below bearing 'l may be provided with a running nt as at it with the lower end of crankcase I to seal the latter. The iiange-type seal 2'! shown in Fig. li may be provided to additionally prevent compression losses within the crank chamber.

According to the invention a yvertical passagesage 30 registers with passage 28 at the lower dead center position of crankshaft just before the pressure within crank chamber I4 has completely diminished so that a small amount of oil is positively discharged into chamber 29 with each crankshaft revolution. The oil passing into the chamber 29 lubricates the spline connection between shaft 5 and driveshaft 2| and passes downwardly and through opening 22 and into the driveshaft housing 20.

The compression in the upper cylinder 3 normally precludes the engine crankshaft 5 from stopping with passage 30 and the lower crank chamber M open to the atmosphere. The possibility of water or moisture entering the crank chamber and subjecting the bearings to corrosion is thus prevented.

When the engine is stopped after running, passage 30 is automatically closed by reason of the fact that the normal cylinder compression in upper and lower cylinders 3 and 4 causes the engine crankshaft 5 to come to rest approximately one-half way between upper and lower dead centers as shown in Fig. 3 or 180 from that shown.

By reason of the fact that passage 30 registers with passages 23 and 3i for only a small part of the cycle of compression in crank chamber I4 near the end of the discharge of fuel from the chamber into cylinder 4, the rate of now through passages 2S, 30 and 3i is held within the desired maximum limits at all speeds and so that there is substantially no loss of useful fuel compression and transfer.

Where the engine remains standing without use the closing of passage 29 prevents the drying of the bearing 0 and the loss of oil remaining in the lower end of the crankcase. When the engine is eventually started the small required amount of oil remaining in passage 28 will be available initially to lubricate the spline-bearing surfaces in opening 24!- and prevent undue noise and wear. The positive discharge of oil prevents excessive amounts of oil to become accumulated within the crank chamber.

Various embodiments of the invention may be employed to lubricate various operating elements within the scope of the accompanying claims.

I claim:

l. in a two-cycle engine having two cylinders, a crankshaft with two corresponding opposite crank throws, a piston within each cylinder and connected to the respective crank throw for reciprocation in the cylinder, a separate crank chamber for each crank throw communicating with the end of the corresponding cylinder beneath the piston and adapted to receive the fuel mixture for precompression by the piston, fuel intake and exhaust ports opening into and from each cylinder and disposed to be closed by the respective piston and otherwise opened thereby with piston reciprocation remote from the combustion end of the cylinder, the combustion end of the cylinder being otherwise closed for compression of the gases therein by the piston and said crank throws being rotationally spaced 180 whereby a crank chamber associated with one cylinder is subject to a period of nominal compression coinciding with a period of maximum compression in the combustion end of the other cylinder, a drain passage from the lower end of one of said crank chambers to provide a gravity discharge for lubricant and excess fuel therefrom, and a valve disposed to open said passage in timed relation with rotation of said crankshaft during said period of maximum compression in the cylinder associated with the other crank chamber, said valve otherwise closing said drain passage, the compression within said last-named cylinder being effective to bias said crankshaft to a position closing said valve and passage upon normal dissipation of inertia forces of the crankshaft when the engine is stopped.

2. In an `outboard motor including a vertical drive shaft and a drive shaft housing therefor, a two-cycle engine having two cylinders and supported by said drive shaft housing, a crankshaft with two corresponding crank throws and having connection with the upper end of said drive shaft in said housing, a piston within each cylinder and connected to the respective crank throw for reciprocation in the cylinder, a separate crank chamber for each crank throw communicating with the end of the corresponding cylinder beneath the piston and adapted to receive the fuel mixture for precompression by the piston, fuel intake and exhaust ports opening into and from each cylinder and disposed to be closed by the respective piston and otherwise opened thereby Awith piston reciprocation remote from the combustion end of the cylinder, the combustion ends of the cylinders being otherwise closed for compression of the gases therein by the piston and said crank throws being rotationally spaced whereby a crank chamber associated with one cylinder is subject to a period of nominal compression coinciding with a period of maximum compression in the combustion end of the other cylinder, a drain passage from the lower end of said last-named crank chamber to said crankshaft connection to utilize the lubricant and excess fuel to lubricate said connection, and a valve disposed to open said passage in timed relation with rotation of said crankshaft during said period of maximum compression in the cylinder associated with the other crank chamber, and said valve otherwise closing said drain passage, the compression within said last-named cylinder being effective to bias said crankshaft to a, position closing said valve and passage upon normal dissipation of inertia forces of the crankshaft when the engine is stopped.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,440,338 Kincarmon Apr. 27, 1948 FOREIGN PATENTS Number Country Date 251,920 Great Britain s May l5, 1926 510,255 Great Britain July 3, 1939 55,886 Sweden Novl 8, 1922 

